J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (12): 2552-2568.DOI: 10.1111/jipb.13571

• Abiotic Stress Responses • Previous Articles     Next Articles

Natural variation in STAYGREEN contributes to low-temperature tolerance in cucumber

Shaoyun Dong1†, Caixia Li1†, Haojie Tian1†, Weiping Wang1, Xueyong Yang1, Diane M. Beckles2, Xiaoping Liu1, Jiantao Guan1, Xingfang Gu1, Jiaqiang Sun3*, Han Miao1* and Shengping Zhang1*   

  1. 1. State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China;
    2. Department of Plant Sciences, University of California, One Shield Avenue, Davis, CA 95616, USA;
    3. Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
    These authors contributed equally to this work.
    *Correspondences:Han Miao(miaohan@caas.cn);Jiaqiang Sun(sunjiaqiang@caas.cn);Shengping Zhang(zhangshengping@caas.cn, Dr. Zhang is fully responsible for the distributions of all materials associated with this article)
  • Received:2023-08-24 Accepted:2023-10-06 Online:2023-10-09 Published:2023-12-01

Abstract: Low-temperature (LT) stress threatens cucumber production globally; however, the molecular mechanisms underlying LT tolerance in cucumber remain largely unknown. Here, using a genome-wide association study (GWAS), we found a naturally occurring single nucleotide polymorphism (SNP) in the STAYGREEN (CsSGR) coding region at the gLTT5.1 locus associated with LT tolerance. Knockout mutants of CsSGR generated by clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated nuclease 9 exhibit enhanced LT tolerance, in particularly, increased chlorophyll (Chl) content and reduced reactive oxygen species (ROS) accumulation in response to LT. Moreover, the C-repeat Binding Factor 1 (CsCBF1) transcription factor can directly activate the expression of CsSGR. We demonstrate that the LT-sensitive haplotype CsSGRHapA, but not the LT-tolerant haplotype CsSGRHapG could interact with NON-YELLOW COLORING 1 (CsNYC1) to mediate Chl degradation. Geographic distribution of the CsSGR haplotypes indicated that the CsSGRHapG was selected in cucumber accessions from high latitudes, potentially contributing to LT tolerance during cucumber cold-adaptation in these regions. CsSGR mutants also showed enhanced tolerance to salinity, water deficit, and Pseudoperonospora cubensis, thus CsSGR is an elite target gene for breeding cucumber varieties with broad-spectrum stress tolerance. Collectively, our findings provide new insights into LT tolerance and will ultimately facilitate cucumber molecular breeding.

Key words: chlorophyll, CRISPR/Cas9, CsSGR, cucumber, GWAS, low-temperature tolerance

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